Abstract

Saturable absorbers are a key component for mode-locking femtosecond lasers. Polymer films containing graphene flakes have recently been used in transmission as laser mode-lockers but suffer from high nonsaturable loss, limiting their application in low-gain lasers. Here, we present a saturable absorber mirror based on a film of pure graphene flakes. The device is used to mode lock an erbium-doped fiber laser, generating pulses with state-of-the-art, sub-200-fs duration. The laser characteristic indicates that the film exhibits low nonsaturable loss (13% per pass) and large absorption modulation depth (45% of low-power absorption).

Received 04 November 2011Accepted 05 December 2011Published online 29 December 2011

Acknowledgments:

This work was supported by the Australian Research Council under DP0773354 (Kielpinski) and by the School of Biomolecular and Physical Sciences and the Queensland Micro- and Nanotechnology Centre, Griffith University (Brown).